package com.fdd.op.sdk.internal.util.json;

import com.fdd.op.sdk.internal.mapping.ApiField;
import com.fdd.op.sdk.internal.mapping.ApiListField;
import com.fdd.op.sdk.internal.mapping.Converters;
import com.fdd.op.sdk.internal.util.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.*;
import java.text.CharacterIterator;
import java.text.StringCharacterIterator;
import java.util.*;

/**
 * JSONWriter
 *
 * @author Fadada
 * @date 2021/04/26
 */
public class JSONWriter {
    private static final Log log = LogFactory.getLog(JSONWriter.class);


    private StringBuffer buf = new StringBuffer();
    private Stack<Object> calls = new Stack<Object>();
    private boolean emitClassName = true;
    private boolean useApiStyle = false;
    private boolean useApiField = false;

    public JSONWriter(boolean emitClassName) {
        this.emitClassName = emitClassName;
    }

    public JSONWriter(boolean emitClassName, boolean useApiStyle) {
        this(emitClassName);
        this.useApiStyle = useApiStyle;
    }

    public JSONWriter(boolean emitClassName, boolean useApiStyle, boolean useApiField) {
        this(emitClassName);
        this.useApiStyle = useApiStyle;
        this.useApiField = useApiField;
    }

    public JSONWriter() {
        this(false);
    }

    public String write(Object object) {
        buf.setLength(0);
        value(object);
        return buf.toString();
    }

    public String write(long n) {
        return String.valueOf(n);
    }

    public String write(double d) {
        return String.valueOf(d);
    }

    public String write(char c) {
        return "\"" + c + "\"";
    }

    public String write(boolean b) {
        return String.valueOf(b);
    }

    private void value(Object object) {
        if (object == null || cyclic(object)) {
            add(null);
        } else {
            calls.push(object);
            if (object instanceof Class<?>) {
                string(object);
            } else if (object instanceof Boolean) {
                bool(((Boolean) object).booleanValue());
            } else if (object instanceof Number) {
                add(object);
            } else if (object instanceof String) {
                string(object);
            } else if (object instanceof Character) {
                string(object);
            } else if (object instanceof Map<?, ?>) {
                map((Map<?, ?>) object);
            } else if (object.getClass().isArray()) {
                array(object);
            } else if (object instanceof Iterator<?>) {
                array((Iterator<?>) object);
            } else if (object instanceof Collection<?>) {
                array(((Collection<?>) object).iterator());
            } else if (object instanceof Date) {
                date((Date) object);
            } else {
                bean(object);
            }
            calls.pop();
        }
    }

    private boolean cyclic(Object object) {
        Iterator<Object> it = calls.iterator();
        while (it.hasNext()) {
            Object called = it.next();
            if (object == called) {
                return true;
            }
        }
        return false;
    }

    /**
     * org.springframework.util.ReflectionUtils.makeAccessible(method);
     */
    private void makeAccessible(Method method) {
        if ((!Modifier.isPublic(method.getModifiers()) ||
                !Modifier.isPublic(method.getDeclaringClass().getModifiers())) && !method.isAccessible()) {
            method.setAccessible(true);
        }
    }

    private void bean(Object object) {
        add("{");
        BeanInfo info;
        boolean addedSomething = false;
        try {
            info = Introspector.getBeanInfo(object.getClass());
            PropertyDescriptor[] props = info.getPropertyDescriptors();
            for (int i = 0; i < props.length; ++i) {
                PropertyDescriptor prop = props[i];

                String name = prop.getName();
                Method accessor = prop.getReadMethod();
                if ((emitClassName || !"class".equals(name)) && accessor != null) {
                    if (!accessor.isAccessible()) {
                        makeAccessible(accessor);
                    }
                    Object value = accessor.invoke(object, (Object[]) null);
                    if (value == null) {
                        continue;
                    }
                    if (addedSomething) {
                        add(',');
                    }
                    if (useApiField) {
                        Field field = null;
                        try {
                            field = Converters.getField(object.getClass(), prop);
                        } catch (Exception e) {
                            log.error("bean error:", e);
                        }
                        if (field == null) {
                            log.error("field is null ");
                            return;
                        }
                        ApiField jsonField = field.getAnnotation(ApiField.class);
                        if (jsonField != null) {
                            name = jsonField.value();
                        }
                        ApiListField jsonListField = field.getAnnotation(ApiListField.class);
                        if (jsonListField != null) {
                            name = jsonListField.value();
                        }
                    } else {
                        if (useApiStyle) {
                            name = StringUtils.toUnderlineStyle(name);
                        }
                    }
                    add(name, value);
                    addedSomething = true;
                }
            }
            Field[] ff = object.getClass().getFields();
            for (int i = 0; i < ff.length; ++i) {
                Field field = ff[i];
                Object value = field.get(object);
                if (value == null) {
                    continue;
                }
                if (addedSomething) {
                    add(',');
                }
                add(field.getName(), value);
                addedSomething = true;
            }
        } catch (IllegalAccessException | InvocationTargetException | IntrospectionException e) {
            log.error("bean error:", e);
        }
        add("}");
    }

    private void add(String name, Object value) {
        add('"');
        add(name);
        add("\":");
        value(value);
    }

    private void map(Map<?, ?> map) {
        add("{");
        Iterator<?> it = map.entrySet().iterator();
        while (it.hasNext()) {
            Map.Entry<?, ?> e = (Map.Entry<?, ?>) it.next();
            value(e.getKey());
            add(":");
            value(e.getValue());
            if (it.hasNext()) {
                add(',');
            }
        }
        add("}");
    }

    private void array(Iterator<?> it) {
        add("[");
        while (it.hasNext()) {
            value(it.next());
            if (it.hasNext()) {
                add(",");
            }
        }
        add("]");
    }

    private void array(Object object) {
        add("[");
        int length = Array.getLength(object);
        for (int i = 0; i < length; ++i) {
            value(Array.get(object, i));
            if (i < length - 1) {
                add(',');
            }
        }
        add("]");
    }

    private void bool(boolean b) {
        add(b ? "true" : "false");
    }

    private void date(Date date) {
        add("\"");
        add(StringUtils.formatDateTime(date));
        add("\"");
    }

    private void string(Object obj) {
        add('"');
        CharacterIterator it = new StringCharacterIterator(obj.toString());
        for (char c = it.first(); c != CharacterIterator.DONE; c = it.next()) {
            if (c == '"') {
                add("\\\"");
            } else if (c == '\\') {
                add("\\\\");
            } else if (c == '/') {
                //add("\\/");
                add("/");
            } else if (c == '\b') {
                add("\\b");
            } else if (c == '\f') {
                add("\\f");
            } else if (c == '\n') {
                add("\\n");
            } else if (c == '\r') {
                add("\\r");
            } else if (c == '\t') {
                add("\\t");
            } else if (Character.isISOControl(c)) {
                unicode(c);
            } else {
                add(c);
            }
        }
        add('"');
    }

    private void add(Object obj) {
        buf.append(obj);
    }

    private void add(char c) {
        buf.append(c);
    }

    static char[] hex = "0123456789ABCDEF".toCharArray();

    private void unicode(char c) {
        add("\\u");
        int n = c;
        for (int i = 0; i < 4; ++i) {
            int digit = (n & 0xf000) >> 12;
            add(hex[digit]);
            n <<= 4;
        }
    }
}
